FIG. 1.

Southern blotting of RT-PCR products relative to the cytokines produced by resting uninfected human macrophages and by resting macrophages infected with two strains of M. tuberculosis (MTB), H37Rv and the CMT97 clinical isolate. Three time points were analyzed for each sample: 1, 3, and 7 days of culture for the controls, and 1, 3 and 7 days after infection for the infected cells. In each of the three groups, the first lane represents uninfected macrophages, the second represents H37Rv-infected macrophages, and the third represents CMT97-infected macrophages. As it comes out from the kinetics of RT-PCR products, the majority of cytokines decrease as a function of time, while the clinical strain induces a stronger and more prolonged production of TNF-α and IFN-γ compared with the laboratory strain H37Rv.